One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,6)(5,8)(9,10)(11,18)(12,16)(13,15)(14,19)(17,21)(20,23)(22,24)(25,26)(27,31)(28,38)(29,34)(30,33)(32,35)(36,40)(37,39) involution — undirected(1,3,4,8)(2,5,6,7)(9,11)(10,14)(12,19)(13,20)(15,22)(16,18)(17,23)(21,24)(25,27,28,35,30,37,29,36)(26,31,38,32,33,39,34,40)(10,15)(13,21)(14,22)(16,17)(18,23)(20,24)(25,27,30,37)(26,32,33,40)(28,36,29,35)(31,34,39,38)(2,6)(5,7)(10,16)(11,19)(15,17)(20,24)(26,33)(31,39)(32,40)(34,38) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.